The present invention relates to a gas turbine combustor which can effectively suppress burning loss generated on the internal wall surface of a tail cylinder due to the catching of combustion gas.
In a gas turbine combustor, there has been conventionally employed a structure which has an opening section of an internal cylinder inserted into a tail cylinder and installed there. FIG. 11 is a cross section of a complete conventional gas turbine combustor. FIG. 12 is an enlarged cross-sectional diagram and FIG. 13 is a front diagram of required portions of the gas turbine combustor shown in FIG. 11. As shown in FIG. 11 to FIG. 13, a gas turbine combustor 100 is constructed of an external cylinder 111 which is installed on a vehicle chamber 110, a tail cylinder 120 which is disposed within the vehicle chamber 110, an internal cylinder 130 which is inserted into and installed on this tail cylinder 120, and an external cylinder casing 112 which positions and fixes the internal cylinder 130 relative to the external cylinder 111. The external cylinder 111 is prepared using a metal member having a circular cylinder section, and is installed on the external side of the vehicle chamber 110, with the circular cylinder section set substantially perpendicular to this external side. The external cylinder 111 is fixed to the vehicle chamber 110 with bolts not shown. The tail cylinder 120 is prepared using a thin metal member, and has a circular cylinder section 121 and a nozzle section, not shown, with a front end of the circular cylinder section 121 curved mildly. The tail cylinder 120 is fixed, with a front end of the nozzle section connected to a combustion path of a turbine not shown. The tail cylinder 120 is installed on the external cylinder 111, with the circular cylinder section 121 inserted into the external cylinder 111. The tail cylinder 120 is positioned substantially on the same axis with the external cylinder 111.
The internal cylinder 130 is prepared using a metal member having a circular cylindrical shape. An opening section 131 of the internal cylinder 130 expands mildly and reaches an internal wall surface 122 of the tail cylinder 120. The internal cylinder 130 has a spring plate 132 made of a metal member, and a sealing plate 133 which is supported with this spring plate 132, on a side wall in the vicinity of the opening section 131. Further, the internal cylinder 130 has a pilot nozzle 140 which jets diffusion flame, and eight main nozzles 141 which are disposed around the pilot nozzle 140 and which jets combustion gas, within the internal cylinder 130. This pilot nozzle 140 has a tubular pilot cone 142 at its front end, and has a pilot fuel jet nozzle 143 inside the tubular pilot cone 142. The main nozzle 141 is extended with a main nozzle extension cylinder 144 in the vicinity of the opening section 131 of the internal cylinder 130, and has a jet section 145 at substantially the same position as the pilot cone 142. A main fuel jet nozzle 145 is disposed inside the main nozzle 141. The pilot nozzle 140 and the main nozzle 141 are fixed to the internal cylinder 130 with a substrate 147 which is installed on the internal wall of the internal cylinder 130.
The internal cylinder 130 is installed on the tail cylinder 120, with the opening section 131 inserted into the tail cylinder 120. The sealing plate 133 of the internal cylinder 130 is biased toward the internal wall of the tail cylinder 120 with the spring plate 132, and seals a section of engagement between the tail cylinder 120 and the internal cylinder 130. The internal cylinder 130 is engaged with the tail cylinder 120 by pressing the sealing plate 133 against the tail cylinder. An entrance 134 of the internal cylinder 130 is supported with the external cylinder casing 112, and the internal cylinder 130 is positioned substantially on the same axis with the external cylinder 111. The internal cylinder 130 is fixed to an aligned position, by having the external cylinder casing 112 fixed to the external cylinder 111 with bolts not shown. The internal cylinder 130 has a stay 135 which takes compressed air 150 into the inside, at the entrance 134. A reference numeral 113 denotes a pilot fuel supply opening 113 from which fuel is supplied to the pilot fuel jet nozzle 143, and reference numeral 114 denotes a main fuel supply opening 114 from which fuel is supplied to the main fuel jet nozzle 146.
In the conventional gas turbine combustor 100, air 150 compressed with a compressor not shown passes through a flow path 115 which is encircled with the external peripheral surface of the tail cylinder 120 and the external peripheral surface of the internal cylinder 130, and the internal peripheral surface of the external cylinder 111. This air enters the internal cylinder 130 from the stay 135. Air 151 which has entered the internal cylinder 130 is mixed with main fuel within the main nozzle 141, and a mixed gas is formed. This pre-mixed air 152 is blown out from the main nozzle extension cylinder 148, and is ignited with the diffusion flame, not shown, which is emitted from the pilot nozzle 140, to form a high-temperature combustion gas 153. This combustion gas 153 is blown out into the tail cylinder 120 from the opening section 131 of the internal cylinder 130, and is combusted within a combustion chamber 125, and the combusted gas is supplied to the turbine.
According to the conventional gas turbine combustor 100, however, there has been a problem that the internal wall of the tail cylinder 120 is damaged by burning with the combustion gas 153 which is blown out from the opening section 131 of the internal cylinder 130. In other words, according to the gas turbine combustor 100 having such a structure that the opening section 131 of the internal cylinder 130 is inserted into and engaged with the tail cylinder 120, the edge of the opening section 131 and the internal wall surface 122 of the tail cylinder 120 are not smoothly connected to each other. Therefore, a gap 124 generated at this connection section catches the high-temperature combustion gas 153 which has been blown out from the opening section 131, and this combustion gas burns the internal wall surface 122 of the tail cylinder 120.
The present invention has been achieved in order to solve the above problems and it is an object of this invention to provide a gas turbine combustor which can effectively suppress burning loss generated on the internal wall surface of the tail cylinder in the vicinity of the opening section of the internal cylinder.
In the gas turbine combustor according to the present invention, compressed air is jetted along an internal wall surface of a tail cylinder from a clearance secured between the internal wall surface of the tail cylinder and an edge of an opening section of an internal cylinder. As a result, a film of cooling air is formed on the internal wall surface of the tail cylinder whereby the internal wall surface of the tail cylinder is protected from a high-temperature combustion gas which is blown out from the opening section of the internal cylinder.
Other objects and features of this invention will become apparent from the following description with reference to the accompanying drawings.